Is Grip Strength a Better Measure of Long Segment Fusion Outcomes than an Established Frailty Index?

Introduction: Grip strength has been established as a valid biomarker for health, has been inversely correlated with all-cause mortality, and directly correlated with length of hospital stay (1). In contrast to the simplicity of grip strength, frailty indexes using numerous data points have been developed. One such measurement, the Five-item Modified Frailty Index, has been successful in predicting postoperative adverse events in patients after spine surgery (2). In this paper, the authors aim to compare the ability of grip strength and the Five-item Modified Frailty Index to predict outcomes in patients undergoing long segment fusions.

Methods: A IRB-approved retrospective chart review was conducted on 23 patients undergoing long segment fusions from 2020-2023. Data was collected on medical comorbidities necessary for calculating frailty based on the Five-item Modified Frailty Index and on post-operative outcomes including discharge location, length of ICU stay, and length of hospital stay (2). Descriptive statistics and analysis were performed using IBM SPSS Statistics and required binary logistic regression and Pearson’s and Spearman’s correlation coefficients with p-value < 0.05 being significant.

Results: First, a binary logistic regression was conducted assessing how grip strength and frailty index impacts whether a patient is discharged home or not. Patients with an increased grip strength were significantly more likely to be discharged home as opposed to a rehabilitation facility (right hand: p=0.023, left hand: p=0.035), while patients with decreased frailty were not.
Pearson’s coefficient was then used to assess a correlation between grip strength and length of stay. Increased grip strength was significantly correlated with a shorter ICU stay (RH: p=0.004, LH: p=0.006), but not with a decreased hospital stay. Spearman’s coefficient was used to find a correlation between frailty index and length of stay. Increased frailty was also significantly correlated with a longer ICU stay (p=0.024), but not with an increased hospital stay.

Conclusion : Although both increased grip strength and decreased frailty are correlated with decreased ICU stay, only increased grip strength is associated with a higher likelihood of patients returning home postoperatively, therefore making grip strength a potentially superior predictor of postoperative outcomes.